[Docop]

Hi

I would like to have the exact data during a drilling of composite material. So is anyone know a system that i can put beside the material and have a monitor to show me the : strain, the thrust force and the feed rate of the drill ?
I know i can put a kind of a dynamometer with a strain gage on it and over a plate of ALu and finally the part to be cut. But a system under 400$ should be interesting.
For the thrust, i have think of a rotary encoder that i might derivate the thrust by : if the speed goes down = some thrust resistance happen...

Thank in advance

[DMF_TomB]

in a pinch a force gage can be made with a hydraulic cylinder with a pressure gage on it. Basically at 100lbs see what gage pressure is psi. if it reads 10 psi at 100lbs then every 10 psi is 100 lbs of force on the cylinder.
......we have made gages before to calibrate a machine like a winder grabbing a cardboard tube so paper can be wound on it. Too low a pressure and a roll weighing tons may fall. Too high a pressure and the cardboard core maybe crushed.
......they sell already made gages but most are not cheap.

[vger]

Many electronic scales use strain guage sensors. You might be able to adapt a scale to use under the material being worked for measuring the force. Monitoring motor current can give you an indication of how much work the drill is doing. Feed rate measurement might be a little tougher.... maybe high count encoder connected to a frequency counter.

Steve

[mike_Kilroy]

what is ur spindle motor? ac? dc? drive on it? vfd? how accurate do u need this thrust reading? .1%? 10%? 50%?

[Docop]

So the motor is an ac one. Maybe i can put also a current meter to let know the raising amp, but i don't know if it will show up great data at the end or how i will be able to interpret it.. or as a calibration process..

Anyway, i see some articles about a dynamometer and sensor, but it was way too overkill for sure. as i don't found any on ebay too .. hehe. The idea of a scale might be interesting.. But does i put c-clamp on the scale base with the part to be drill and after i just redo the Zero ?

[mike_Kilroy]

what is ur spindle motor? ac? dc? drive on it? vfd? how accurate do u need this thrust reading? .1%? 10%? 50%?

ok so it is an ac motor, so it is harder to use motor current to figure load. but is there a drive on it? if so, what model/brand? how accurate you need?

If there is a vfd on it, it probably has a load meter output that will do exactly what you want.

If no vfd on it, would you consider adding one to get this load meter feature? Is it 230v? 1ph power? 3phase? what hp? You say upto $ 400 is in the ballpark.... what size is it?

How accurate do you need?